David mcfarland



nitrh -faire @anni @High DAVID. MCEERLEND, 0E NEW Yoan, N; Y., AssieNoE To JOHN JoENsAoN,

OF SAME PLACE.

" Lam Manilva. Metadaten July 7,1868.Y

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lTo ALE WHoMrr MAY-CONCERN:

4:Beit knownthat I, DAVID VI lIclzTRLAND, oi' the city, county, and State of New York, have invented a new and useful Low-WaterDetector and-'Steam-Pressure Alarm; and I do hereby' declare that the following is a full, clear, and exact description thereo`, whichvill enable othersskilled inthe art to'make and'use thesame,

reference being had to the accompanying drawing, forming a part of this specification.

This invention relates to anew and simple device to be connected witha steam-boiler forsounding an alarm when thesteam within the boiler exceeds a certain pressure, and alsdfcrsounding anv alarm when the water descends to a certain level. i

In the accompanying drawing an elevation of my invention is shown', the'side ot'the box or case nearest the eye being reinoved.- v i I l v A- repres'ents a box or casehaving two cninpartments,-B`C, B being placed-belowtlie other, C, and B'con'j siderably larger-than C, as shown-clearlyin the drawing. 'i

The upper and smaller compartment, C, communicates, by means of a pipe, D, with the steam-boiler above the level of the water therein, and the lower and larger compartment, B, communicates with Vthe steam-boiler below the water-level, by'means of pipesE F,` the pipe E communicating with B near' its bottomwhile E com- A municate's with it somewhathiigher up, and extends upward in B to 'within :a sbortdistance' of its top, as shown in the drawing. 1 i I Y Within the compartment -B there is placed a box, G, which is tted on a rodor shaft, a, at the bottom of B, and is ccunterpoised by a weight, H, when the compartment'B is iilled withrwater from the boiler.v This box G has openings in its top, onecr more,so that it will be filled -when Bliis illed; the box:G having no dischargeapertures, as itis designedto have it contain water permanently.

I is 'au sliding rod, which passes through a stuiling-box, b, in the partition between B and C, and'has shoulders, c c', upon it, toA limit its movement;4 and J is'the valve of a st eam-whistle, K, the stem d of said valve 'being connected to the rod- Ibya pin,' e, which passes, through an oblong slot`,f, in the stern'd, and admits of n certainl .length ot'lmovue'mcnt of the stern independent of the rod I,`as will be fully understood.` by referring to the drawing, v l

Y The lower end of the rod is,.'pivoted to n. bar,`.L, the lower end' of which is pivoted to theA upper surface of the bottom ofthe box-G,

M represents an ordinarysafety-valve, N being the loaded beam, which bears upon the-'upper .end of the .valve-stem gf The valve'M has a' pendent loop, h, attached, through which one end'of la lever, O, in the compartment C,passes, theopposite end ci' said lever bearing upon a piu, z', which passes through the stem cl.

The operation is asfollows:l 4 The compartment B,y where thepipe E is. below the water-level. in theboiler, islled with water, and the box G is also illediivith wat'erfrom '13, and the buoyancy of the box, inconnection with thhweight H, rcauses' v 4thcbox to remain ina-state of" equipois'e so long as'Bu-emains filled withwate'r. The box G, while thus equipoised, keeps theivajlve Leith-c st eam-whistlcK in a closed state, as will be fully understood by referring to the drawing.

The'corfnpartnient C is', ofcourse, filled with steam from the boiler, and by'adjusting the weight P on'the beam N according to rthe 'steam-pressure required in the'boiler,`the valve M will not be raised by the pressure of" steamfin C until the'required pressure isexceeded, and when this occurs, and the valve M is raised, the lever Ois at the saine time'actuated, the stemt?, andconsequently the' valve J,are forced down, and the whistle or Valarm sounded, v I f I i This movement ofthe valve 'J o`f` t`he whistle,independent of the ro'd' I, is allowed'in consequence of the piu e, whichconnects'- the stem'clto -rod I, passing through the oblong slotf.i n CZ.-

Y Thus it will be seen that .whenever the steam-pressure in the boiler exceeds the required standard, the whistle or alarm will be sounded simultaneously with the opening of the safety-valve.

The evaporation vof'thewatei` in the boiler below the proper level is indicated as follows: -As before stated,

when the'lower oriee. of pipeF is below the water-level in the boiler, (the other pipe, E, always being below it,)

the compartment B willbe tilled with water, owing-tothe pressure ofthe steam on thesurface of the water in theiboiler, and the box G willpbe in a state of equipoise,'and the whistle or alarm-valve J kept closed. When, however, the water in the boiler descends below the lower orifice of pipe F, the steam will rush up through the latter into compartment B; and the water in B iniufiediatelyV descends, passing through E into the boiler until the water-level iu boiler is reached, when B will be nearly or quite emptied.` Y

The box G will then, owing to the absence of thebuoyant power ofthe water, tilt in the direction indicated by the arrow, and in so doing draw down or open the valve J, and the whistle `or alarm will be sounded.

s the boiler is replenished with water, the compartment B will be again filled, and the box G buoyed up toelose the valve J and keep it in a closed state.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. The tilting-box G, fitted within a compartment, B, which communicates with the steam-bciler below the water-level by pipes E F, and is connected with the valve J of a steam-whis`tle or alarm, K, all arranged to operate in the manner substantially as and for the purpose described.

2. The safety-valve M, connected with the valve J of the steam-whistle or alarm by means of the lever O and the stem d of valve J, arranged within a steam-eompartment, 0,*as shown, to admit of a. movement of said valve independent of the rod I and box G, and the simultaneous opening of the safety-valve M and whistle or alarm-valve J, when the steam within the boiler exceeds a certain desired pressure.

DAVID MGFARLAND.

Wit'nesse:

FRANK BLoeKLEY, ALEX. F. RBERTS. 

